[amd] screen-unblanking seems to flicker backlight on/off 8 times before display resumes

Bug #1667001 reported by Gerry Boland on 2017-02-22
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Canonical System Image
Undecided
Unassigned
Mir
New
Undecided
Unassigned
repowerd
Undecided
Unassigned
mir (Ubuntu)
Undecided
Unassigned
repowerd (Ubuntu)
Undecided
Unassigned
unity8 (Ubuntu)
Undecided
Unassigned

Bug Description

I've a Lenovo Flex 2-14D which has an AMD GPU. I'm using the free driver. I have unity8 installed.

If I let the screen blank, and hit a key to unblank, it takes about 5 seconds until screen turns on properly. During those 5 seconds, I see the display backlight turn on & off about 5 times, all the while with a black picture.

Daniel van Vugt (vanvugt) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:
apport-collect 1667001

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

Changed in canonical-devices-system-image:
status: New → Incomplete
Changed in mir:
status: New → Incomplete
Changed in repowerd:
status: New → Incomplete
Changed in mir (Ubuntu):
status: New → Incomplete
Changed in repowerd (Ubuntu):
status: New → Incomplete
Changed in unity8 (Ubuntu):
status: New → Incomplete
Daniel van Vugt (vanvugt) wrote :

Oops, sorry Gerry. Didn't realize it was you :)

Alexandros Frantzis (afrantzis) wrote :

Could you please attach /var/log/repowerd.log at the time of the issue.

Gerry Boland (gerboland) wrote :

Ok, with Alexandros' help I've dug a bit more.

On my hardware, I tear everything down and just run
    sudo mir_demo_server_basic --arw-file
I can see clients ok.

I forked mir_demo_client_display_config to add extra bits:
https://code.launchpad.net/~gerboland/+git/display-configurator
which adds an "O" option to power off the display

When I run it, and hit "O", the display flickers 8 times and then stays off (mir_power_mode_off)

If I hit "P" to turn it on again, nothing happens (mir_power_mode_on). Applying the configuration appears to hang the client - I get no success or fail response from Mir.

If I kill the client, Mir re-activates the display (flickering 8 times)

Changed in mir:
status: Incomplete → New
Changed in unity8 (Ubuntu):
status: Incomplete → Invalid
Changed in repowerd (Ubuntu):
status: Incomplete → Invalid
summary: - [amd] screen-unblanking seems to flicker backlight on/off 5 times before
+ [amd] screen-unblanking seems to flicker backlight on/off 8 times before
display resumes
Changed in repowerd:
status: Incomplete → Invalid
Gerry Boland (gerboland) wrote :

One small warning message is printed during display on flicker:
http://pastebin.ubuntu.com/24053776/

Daniel van Vugt (vanvugt) wrote :

That warning might indeed correlate with some flicker:

[2017-02-23 16:18:58.483124] <WARNING> mesa-kms: drmModeCrtcSetGamma failed: Invalid argument

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